What Can Be Done About Antibiotic-Resistant Food-Borne Illness?

The Centers for Disease Control (CDC) released a report on September 16, 2013 to inform the public about recent developments in its fight against antibiotic resistance and the status of the current threat. Most of the CDC’s report focused on antibiotic resistant (AR) hospital-acquired infections. There are estimates that about 50 percent of antibiotics prescribed for human use in the United States are not necessary or appropriate, and the CDC recommends that prescribers use antibiotics more judiciously. But the CDC also found that the widespread use of medicated animal feed has contributed to the development of AR strains of that cause serious illness.

The Use of Antibiotics in Animal Feed

More kilograms of antibiotics are sold in the United States for use with food-producing animals than for human use. And most of the antibiotics given to animals are not used to treat ill or injured animals. Rather, they are given to entire herds or flocks in their feed or water for subtherapeutic, or “production” use, to accelerate growth or weight gain so that the animal may be brought to market earlier. “Subtherapeutic” levels are quantities too low to cure disease, but they do kill bacteria. The problem is that the bacteria that aren’t killed become resistant to the antibiotic, meaning that the drug will not be effective against the same bacteria when it causes illness in an animal or a person.

According to the CDC, salmonella,campylobacter and some other bacteria that develop resistance are transmitted from these animals to humans and can cause serious illness or death. The agency has classified both campylobacter and nontyphoidal salmonella as presenting serious risks to public health due to antibiotic resistance. Antibiotic-resistant campylobacter, which is spread through undercooked chicken, raw milk, contact with animals or contaminated water, is found in many countries, so that international travelers may be at increased risk. Nontyphoidal salmonella causes about 1.2 million illnesses each year in the United States, resulting in 23,000 hospitalizations and 450 deaths. The CDC says that about 100,000 cases per year show some resistance to antibiotics. About 5 percent of cases are resistant to five or more antibiotics.

CDC’s Response

Because food-borne AR infections may be spread either between animals and humans or among humans, CDC finds it necessary to partner with the FDA and the U.S. Department of Agriculture (USDA) as well as state and local entities. Together, the agencies formed the National Antimicrobial Resistance Monitoring System (NARMS) to track developments, conduct research, and disseminate information about ways to prevent the spread of AR infections. NARMS tests samples for resistance to various antibiotics and attempts to monitor the source of each outbreak. One of its purposes is to help the FDA make informed decisions about safe and effective antibiotics to approve for use in animals.

The FDA’s Actions

The FDA’s Guidance on the Judicious Use of Medically Important Antimicrobial Drugs in Food-Producing Animals (GFI 209), finalized in April 2012, recognized the development of antibiotic resistance in food-producing animals and transmission of the AR germs to human beings as a serious threat to public health. The FDA defined “medically important” to mean drugs that are important for therapeutic use with humans, and the guidance stated clearly that production uses are not a judicious use of antibiotics. The Guidance, which does not impose any binding obligations, states that these antibiotics should be used with food-producing animals only when necessary to assure animal health and only under the supervision of or in consultation with a veterinarian.

The FDA issued this guidance shortly after a federal court ordered it to act on citizen petitions to withdraw approval of two antibiotics most frequently used for production. The petitions had been pending since 1999 and 2005. The court found that FDA had not processed the petitions because it would have to give notice to the sponsors of the drugs and participate in hearings, which would be expensive and take many years. Because these factors were not listed in the statute governing the treatment of such petitions, the court held that the agency’s action was arbitrary and capricious. The agency has appealed.

Finally, in Draft Guidance, the FDA suggests that drug sponsors be given three years from the date the draft is finalized to come into voluntary alignment with GFI 209.